Pope Francis has confirmed that he will personally be attending the summit along with 180 participants, including the heads of around 100 bishops' conferences from every continent from across the world.

The summit will be covering two central themes: the root causes and how to make clerics responsible and accountable for sexual abuse, and the most effective ways that the church can help the abuse victims to heal.

The pontiff, however, said earlier this month that expectations for the Vatican summit should be not be high.

He said the issues surrounding clerical sexual abuse were not only deep-rooted, but still continued to exist, and were unlikely to be resolved through the Vatican summit.

His efforts to lower expectations have disappointed advocates for abuse victims as well as the church officials who have long pushed for the leaders to take abuse more seriously.

Activists are already vociferous about the crisis, with Ending Clerical Abuse (ECA) organization demanding that zero tolerance for sexual abuse by clerics be "written into universal church law by the end of the summit."

The organization, which brings together activists and survivors from more than 17 countries, demands that any cleric found guilty of child abuse or cover-up of abuse - regardless of how long ago the crime took place - be defrocked.

The Vatican must "fire any and all bishops or cardinals who have had a hand in clergy sex abuse cover-ups," the Survivors Network of those Abused by Priests said.